JPH10224882A - Hybrid parabolic sound collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound collector for efficiently collecting sounds at distant places. SOLUTION: This hybrid parabolic sound collector for collecting sounds from distant places is provided with a parabolic reflector 1 turning its parabolic concave toward a sound source, microphone 3 of sub-cardioid characteristics installed at the focal point of parabolic reflector while being turned opposite, and superdirective microphone 2 installed on the center line of parabolic reflector closer to the side of sound source adjacently with the microphone 3 of sub-cardioid characteristics while being turned toward the sound source. Then, the outputs of both the microphones are synthesized so as to clearly collect the sounds from distant places.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound pickup device for clearly picking up distant sounds, and more particularly to a device for attaching a plurality of microphones to a parabolic reflector and electrically synthesizing the outputs of the microphones.

[0002]

2. Description of the Related Art Conventionally, in order to pick up a distant sound, the sound is picked up using only a super-directional microphone, or the sound is collected at one focal point using a parabolic sound pick-up device (parabolic reflector). There was a method of collecting sound by installing an omnidirectional microphone at the focus.

[0003]

SUMMARY OF THE INVENTION As described above,
When sound is picked up using only the super-directional microphone, there is a disadvantage that the sound from the back is also picked up at the same time because the super-directional microphone has the directivity in the direction opposite to the sound source in principle ( (See FIG. 2D).

[0004] As shown in FIG. 3 (a), in a combination of a parabolic reflex 1 and an omnidirectional microphone 5,
As shown in the directivity characteristic of (b), there is a drawback that the pattern has a spread, and unnecessary side sounds are also picked up at the same time. SUMMARY OF THE INVENTION It is an object of the present invention to provide a hybrid parabolic sound pickup apparatus that effectively collects only a sound source from a distant place and does not pick up unnecessary sound from the side and the back. .

[0005]

In order to achieve this object, a hybrid parabolic sound pickup apparatus according to the present invention is directed to a sound pickup apparatus for picking up distant sounds, wherein the concave surface of the parabola is directed toward the sound source. A reflector, a microphone having a sub-cardioid characteristic installed at the focal point of the parabolic reflector in a direction opposite to the sound source, and a center line of the parabolic reflector closer to the sound source than the microphone having the sub-cardioid characteristic And a means for combining the outputs of both microphones, which are arranged so as to be directed to the direction of the sound source, and are configured to clearly pick up a distant sound. is there.

In a preferred embodiment of the present invention, the synthesizing means further comprises means for changing a synthesizing ratio of both microphone outputs.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a parabolic sound pickup (parabolic reflex) is used to cut off unnecessary sound from the back and side when sound is picked up by a super-directional microphone. Further, in order to increase the sensitivity of the microphone, a microphone having a sub-cardioid characteristic is placed at the focal point of the parabolic reflex in a direction opposite to the sound source, and this output is added to the output of the super-directional microphone. That is, conventionally, the omnidirectional microphone is placed at the focal position, but by adding a microphone having a sub-cardioid characteristic, unnecessary back and side sounds can be removed.

Also, the present invention provides a variable output synthesis ratio between a super-directional microphone and a microphone having a sub-cardioid characteristic (specifically, a combination of a super-directional microphone and a microphone having a sub-cardioid characteristic). The outputs are each combined via an amplifier), and the overall directivity pattern can be varied as desired.

The present invention will be described more specifically with reference to the accompanying drawings. FIG. 1 shows a configuration example according to the embodiment of the present invention. In the figure, the super-directional microphone and the microphone having the sub-cardioid characteristic are shown enlarged relative to the parabolic reflector in order to make the relative positions of both microphones clearer.

In FIG. 1, reference numeral 1 denotes a parabolic sound collector (parabolic reflector), the concave surface of which is directed toward the sound source. At the focal point on the center line 4 of the parabolic reflector, a microphone 3 having a sub-cardioid characteristic directed in the opposite direction to the sound source is installed. A super directional microphone 2 directed toward the sound source is provided on the center line 4 on the side.

In this embodiment, when sound from a distance is picked up by the super-directional microphone 2, a parabolic reflector 1 is used to cut off unnecessary sound from the back. Further, in order to improve the sound pickup efficiency, a microphone 3 having a sub-cardioid characteristic is placed at the focal point of the parabolic reflex in a direction opposite to the sound source, and the output of this microphone is set to a super-directional microphone 2.
In addition to the output.

FIG. 2A shows the directivity characteristics obtained from the super-directional microphone 2 in the sound pickup device having the configuration shown in FIG. 1, and FIG. 2B shows the directivity characteristics obtained from the microphone 3 having the sub-cardioid characteristics in the same device. (C) shows the combined directional characteristics of (a) and (b). In the directivity characteristic diagram, the 0 ° direction represents the direction of the sound source, and the 180 ° direction represents the direction of the parabolic sound pickup device. Further, the circles in the figure have an interval of every 6 dB. FIG. 4D shows the directivity characteristics when sound is collected using only the conventional super-directional microphone for comparison.

2 (c) and FIG. 2 (d), FIG.
In (c), the sensitivity is high in the 0 ° direction and the sensitivity is low in the 180 ° direction. Further, comparing FIG. 2C with FIG. 3B, in FIG. 2C, the sensitivity is high in the 0 ° direction, and the sensitivity is low in the 180 ° direction and the 90 ° and 270 ° directions. Thus, in FIG. 2C, the sensitivity is high in the direction of the sound source, and the sensitivity is low in the back and side directions.

From these characteristics, the directivity characteristic of the sound pickup apparatus according to the present invention (FIG. 2C) is different from the directivity characteristic when only the conventional directional microphone is used (FIG. 2D). It can be seen from the directivity characteristic (FIG. 3B) when the parabolic reflector and the omnidirectional microphone are combined that the directivity is excellent.

Further, the output ratio between the super-directional microphone 2 and the microphone 3 having the sub-cardioid characteristic can be varied, and the overall directivity pattern changes from FIG. 2 (c) to (a). can do. By these,
By selecting a directivity pattern according to the surrounding situation and synthesizing the outputs of the super-directional microphone and the microphone having the sub-cardioid characteristic, it is possible to collect sound with the intended directivity pattern.

Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications and changes can be made within the gist of the invention described in the claims. It is obvious. For example, the microphone having the sub-cardioid characteristic can be replaced with a microphone having the cardioid characteristic.

[0017]

According to the sound pickup apparatus of the present invention, it is possible to more effectively pick up only a target sound source at a distant place, so that unnecessary sounds from the side and back surfaces can be eliminated. In addition, it is possible to perform sound collection having an intended directivity characteristic by electrically synthesizing a super-directional microphone and a microphone having a sub-cardioid characteristic used in the sound collection device of the present invention in any desired ratio. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a sound pickup device of the present invention.

FIG. 2 is a diagram showing directivity characteristics of various microphones or a combination thereof.

FIG. 3 is a diagram showing an example (a) of a conventional sound collecting device and its sound collecting directivity characteristics (b). DESCRIPTION OF SYMBOLS 1 Parabolic reflector 2 Super-directional microphone 3 Sub-cardioid characteristic microphone 4 Center line of parabolic reflector 5 Omni-directional microphone

Claims (3)

[Claims] 1. A sound pickup device for picking up sound from a distant place, wherein a parabolic concave surface of the parabolic reflector is directed toward a sound source, and a focal point of the parabolic reflector is set in a direction opposite to the sound source. A microphone having a sub-cardioid characteristic, a super-directional microphone placed adjacent to the microphone having the sub-cardioid characteristic and located on the center line of the parabolic reflector on the sound source side toward the sound source, and Means for synthesizing outputs, and configured to clearly pick up distant sounds. 2. An apparatus according to claim 1, wherein said means for synthesizing further comprises means for varying a synthesis ratio of both microphone outputs. 3. The apparatus according to claim 1, wherein
A hybrid parabolic sound pickup device, wherein the microphone having the sub-cardioid characteristic is replaced with a microphone having the cardioid characteristic.